- "Commander, this is extortion!"
"Hmm... yes, it is."
In "solving" the mystery of the Sherlock Holmes story "A Scandal in Bohemia", Data described how a photograph of the King of Bohemia and his mistress would be used in blackmail. (TNG: "Elementary, Dear Data")
Vaatrik Pallra extorted large sums of money from eight Bajoran people, by threatening to publish a list she had found, identifying them as collaborators with the Cardassians during the Occupation of Bajor. (DS9: "Necessary Evil")
Odo deputized Quark by threatening to throw him in jail unless Quark helped discover where illicit weapons being funneled to the Alliance for Global Unity were being stored on Bajor. (DS9: "The Circle")
Benjamin Sisko extorted Elim Garak's assistance on a mission to Cardassia Prime to rescue Kira Nerys from the Obsidian Order by threatening Garak with removal from Deep Space 9 if he did not. Sisko claimed that several Ministers in the Bajoran Provisional Government wanted Garak removed from the station and that Sisko saw little reason to not comply with their request, unless Garak could show how he might be useful. (DS9: "Second Skin")